During mammography, a patient's breast is placed under compression by opposing plates attached to a mammography unit. Once under compression, an x-ray may be taken to determine the presence or absence of suspect lesions in the breast tissue, e.g., calcifications or tumors. An important reason for compressing the breast during mammography is to provide a thinner cross-section of tissue for the x-rays to pass through. When the breast is compressed, it may provide optimal imaging of tissue abnormalities and/or may allow lower doses of x-ray radiation to be used, thereby reducing x-ray radiation exposure to the patient.
FIGS. 1, 2A, and 2B show a mammography unit 10, including a base 12 and a rotating assembly 14 that includes an x-ray source 16, a compression paddle 18, and an x-ray plate 20. The x-ray plate 20, often referred to as a “bucky,” is stationary relative to the assembly 14, while the compression paddle 18 may be attached to an interchange assembly 22 that is movable relative to the x-ray plate 20.
As best seen in FIG. 2A, the x-ray plate 20 generally includes two patient contact surfaces, a primary tissue contact surface 24 and a front surface 26, as well as side surfaces 28. At least one of the side surfaces 28 may include an opening 30 into which an x-ray cassette 32 may be inserted. As best seen in FIG. 2B, the compression paddle 18 also generally includes two patient contact surfaces, a primary tissue contact surface 34 and a front surface 36, as well as two side surfaces 38. Additional configurations of compression plates and accessories that may have various shapes and sizes depending upon a patient's anatomy and/or the type of x-ray view are shown in U.S. Pat. Nos. 6,577,702 and 6,765,984, the entire disclosures of which are expressly incorporated by reference herein.
With the patient (not shown) leaning against the front surfaces 26, 36, the patient's breast (also not shown) is placed on the primary contact surface 24 of the x-ray plate 20 and the compression paddle 18 is moved towards the x-ray plate 20 to compress the breast between the primary contact surfaces 24, 34. A series of x-rays may be taken of the breast tissue, e.g., which may involve moving the assembly 14 and/or repositioning the patient's breast after one or more film exposures.
One of the problems with mammography is that the patient may experience significant discomfort during compression of the breast. Because of this, some women may avoid having a mammogram taken rather than experience the pain that may be caused during the procedure. Although patients may tolerate the pain caused by compression up to about ten to eleven (10-11) compression units, clinical mammography may involve up to sixteen to eighteen (16-18) compression units. If greater compression is used, the quality of the mammogram may be enhanced, thereby increasing the physician's ability to detect cancers or suspect lesions. However, with greater compression comes increased discomfort.
U.S. Pat. No. 5,541,972, issued to Anthony, discloses a padding device that may be added to cover the front surface of an x-ray plate. Because the padding device is made from materials that may be radiopaque, the padding device is generally positioned to avoid disposing it within the field of the x-ray plate.
U.S. Pat. No. 5,185,776, issued to Townsend, discloses a radiolucent pad that is glued to a sleeve. An x-ray cassette may be inserted into the sleeve, a patient may be disposed against the pad, and an x-ray image obtained. The sleeve and pad are disposed of after the x-ray procedure. Disposing of the entire x-ray sleeve after a single use, however, may increase the cost of x-ray procedures.
Accordingly, devices and methods for cushioning compression surfaces, e.g., during mammography, would be useful.